Lipari is a land of promise to the geologist, on account of the great variety of its lavas. Monte della Castagna is wholly composed of obsidian. Another hill, Monte Bianco, consists of pumice, and, when seen from a distance, has the appearance of being covered with snow. The streams of pumice which fill every ravine extend down to the sea, and the water is covered with this buoyant stone, which drifts sometimes as far as Corsica. Lipari supplies nearly the whole of Europe with pumice.[113]

Vulcano, to the south of Lipari, from which it is separated by a strait less than a mile across, contrasts strangely with its smiling neighbour. Vulcano, with the exception of a few olives and vines growing on the southern slopes, consists wholly of naked scoriæ, and this circumstance probably led to its being dedicated to Vulcan. Most of its rocks are black or of a reddish hue like iron, but there are {333} others which are scarlet, yellow, or white. At the northern extremity of the island rises the Vulcanello, a small cone which appeared above the surface of the sea nobody knows when, and which an isthmus of reddish cinders united about the middle of the thirteenth century to the principal volcano of the island. This central mountain of the island has a crater about 1,800 yards in circumference, from which steam continually escapes. The atmosphere is charged with sulphurous vapours difficult to breathe. From hundreds of small orifices jets of steam make their escape with a throbbing and hissing noise. Some of these fumaroles have a temperature of 610° F. Jets of a lower temperature are met with in other parts of the island, and even at the bottom of the bay. Violent eruptions are rare, and in the eighteenth century only three occurred. The last eruption took place in 1873, after a repose of a hundred years. Until recently the only inhabitants of Vulcano were a few convicts, who collected sulphur and boracic acid, and manufactured a little alum. But an enterprising Scotchman has now taken possession of this grand chemical laboratory. He has built a large manufactory near the port, and a few trees planted around his Moorish residence have somewhat improved the repulsive aspect of the country.

Stromboli, though smaller than either Lipari or Vulcano, is nevertheless more celebrated, on account of its frequent eruptions. For ages back scarcely any mariners have passed this island without seeing its summit in a state of illumination. At intervals of five minutes, or less, the seething lava filling its caldron bubbles up, explosions occur, and steam and stones are ejected. These rhythmical eruptions form a most agreeable sight, for there is no danger about them, and the olive groves of the Stromboliotes have never been injured by a stream of lava. The volcano, however, has its moments of exasperation, and its ashes have frequently been carried to the coast of Calabria, which is more than thirty miles off.

Panaria and the surrounding group of islands between Stromboli and Lipari have undergone many changes, if Dolomieu and Spallanzani are correct in saying that they originally formed only a single island, which was blown into fragments by an eruption having its centre near the present island of Dattilo. A hot spring and an occasional bubbling up of the sea-water prove that the volcanic forces are not yet quite extinct.

As regards the small eastern islands of the archipelago, Salina, Felicudi, and Alicudi, the last of which resembles a tent pitched upon the surface of the water, history furnishes no records of their ever having been in any other than a quiescent state. The island of Ustica, about thirty miles to the north of Palermo, is likewise of volcanic origin, but is not known ever to have had an eruption. It is one of the most dreaded places of exile in Italy. Near it is the uninhabited island of Medico, the ancient Osteodes, where the mercenaries deserted by the Carthaginians were left to die of starvation. {334}

THE ÆGADIAN ISLANDS.

Off the western extremity of Sicily lie shallows, sand-banks, and calcareous islands of the same composition as the adjoining mainland. These are the Ægades, or Goat Islands, named after the animals which climb their steep escarpments. Favignana, near which the Romans won the naval victory which terminated the first Punic war, is the largest of these islands. Its steep cliffs abound in caverns, in which heaps of shells, gnawed bones, and stone implements have been found, dating back to the contemporaries of the mammoth and the antediluvian bear. Conflicts between contrary winds are frequent in this labyrinth of rocks and shoals, and the power of the waves is much dreaded. The tides are most irregular, and give rise to dangerous eddies. The sudden ebb, locally known as marubia, or “tipsy sea” (mare ubbriaco?), has been the cause of many shipwrecks.

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Fig. 123.—THE MEDITERRANEAN TO THE SOUTH OF SICILY.